Remove dependency to Kotlin compiler in build tools just because of DFS

(cherry picked from commit 6d9a9e743de6323c0073e09e53c14674ac726f7e)

build-tools/build.gradle.kts

@@ -43,13 +43,9 @@ repositories {
     maven("https://dl.bintray.com/kotlin/kotlin-dev")
 }
 
-val kotlinCompilerJar by configurations.creating
-
 dependencies {
     compileOnly(gradleApi())
 
-    kotlinCompilerJar("org.jetbrains.kotlin:kotlin-compiler:${kotlinVersion}@jar")
-
     implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion")
     implementation("org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion")
     implementation("org.jetbrains.kotlin:kotlin-reflect:$kotlinVersion")
@@ -104,7 +100,6 @@ compileKotlin.apply {
 // Add Kotlin classes to a classpath for the Groovy compiler
 compileGroovy.apply {
     classpath += project.files(compileKotlin.destinationDir)
-    classpath += kotlinCompilerJar
     dependsOn(compileKotlin)
 }
 

build-tools/src/main/kotlin/org/jetbrains/kotlin/utils/DFS.kt

@@ -0,0 +1,121 @@
+package org.jetbrains.kotlin.utils
+
+import java.util.*
+
+// Copied from Kotlin org.jetbrains.kotlin.utils.DFS class
+@Suppress("MemberVisibilityCanBePrivate", "MemberVisibilityCanBePrivate", "unused")
+object DFS {
+    fun <N, R> dfs(nodes: Collection<N>, neighbors: Neighbors<N>, visited: Visited<N>, handler: NodeHandler<N, R>): R {
+        for (node in nodes) {
+            doDfs(node, neighbors, visited, handler)
+        }
+        return handler.result()
+    }
+
+    fun <N, R> dfs(
+            nodes: Collection<N>,
+            neighbors: Neighbors<N>,
+            handler: NodeHandler<N, R>
+    ): R {
+        return dfs(nodes, neighbors, VisitedWithSet(), handler)
+    }
+
+    fun <N> ifAny(
+            nodes: Collection<N>,
+            neighbors: Neighbors<N>,
+            predicate: Function1<N, Boolean>
+    ): Boolean {
+        val result = BooleanArray(1)
+        return dfs(nodes, neighbors, object : AbstractNodeHandler<N, Boolean?>() {
+            override fun beforeChildren(current: N): Boolean {
+                if (predicate.invoke(current)) {
+                    result[0] = true
+                }
+                return !result[0]
+            }
+
+            override fun result(): Boolean {
+                return result[0]
+            }
+        })!!
+    }
+
+    fun <N, R> dfsFromNode(node: N, neighbors: Neighbors<N>, visited: Visited<N>, handler: NodeHandler<N, R>): R {
+        doDfs(node, neighbors, visited, handler)
+        return handler.result()
+    }
+
+    fun <N> dfsFromNode(
+            node: N,
+            neighbors: Neighbors<N>,
+            visited: Visited<N>
+    ) {
+        dfsFromNode(node, neighbors, visited, object : AbstractNodeHandler<N, Void?>() {
+            override fun result(): Void? {
+                return null
+            }
+        })
+    }
+
+    fun <N> topologicalOrder(nodes: Iterable<N>, neighbors: Neighbors<N>, visited: Visited<N>): List<N> {
+        val handler = TopologicalOrder<N>()
+        for (node in nodes) {
+            doDfs(node, neighbors, visited, handler)
+        }
+        return handler.result()
+    }
+
+    fun <N> topologicalOrder(nodes: Iterable<N>, neighbors: Neighbors<N>): List<N> {
+        return topologicalOrder(nodes, neighbors, VisitedWithSet())
+    }
+
+    fun <N> doDfs(current: N, neighbors: Neighbors<N>, visited: Visited<N>, handler: NodeHandler<N, *>) {
+        if (!visited.checkAndMarkVisited(current)) return
+        if (!handler.beforeChildren(current)) return
+        for (neighbor in neighbors.getNeighbors(current)) {
+            doDfs(neighbor, neighbors, visited, handler)
+        }
+        handler.afterChildren(current)
+    }
+
+    interface NodeHandler<N, R> {
+        fun beforeChildren(current: N): Boolean
+        fun afterChildren(current: N)
+        fun result(): R
+    }
+
+    interface Neighbors<N> {
+        fun getNeighbors(current: N): Iterable<N>
+    }
+
+    interface Visited<N> {
+        fun checkAndMarkVisited(current: N): Boolean
+    }
+
+    abstract class AbstractNodeHandler<N, R> : NodeHandler<N, R> {
+        override fun beforeChildren(current: N): Boolean {
+            return true
+        }
+
+        override fun afterChildren(current: N) {}
+    }
+
+    class VisitedWithSet<N> @JvmOverloads constructor(private val visited: MutableSet<N> = HashSet()) : Visited<N> {
+        override fun checkAndMarkVisited(current: N): Boolean {
+            return visited.add(current)
+        }
+    }
+
+    abstract class CollectingNodeHandler<N, R, C : Iterable<R>> protected constructor(protected val result: C) : AbstractNodeHandler<N, C>() {
+        override fun result(): C {
+            return result
+        }
+    }
+
+    abstract class NodeHandlerWithListResult<N, R> protected constructor() : CollectingNodeHandler<N, R, LinkedList<R>>(LinkedList<R>())
+    class TopologicalOrder<N> : NodeHandlerWithListResult<N, N>() {
+        override fun afterChildren(current: N) {
+            result.addFirst(current)
+        }
+    }
+}